•Unseasonably early cold snap in the upper mid-west and eastern
Canada may have affected breeding cycle and/or migration.
•It is known that rodent populations were down at least in some
parts of eastern Canada, and lack of food may have resulted in poor
breeding season, and
•Continuing low rodent populations, may have caused adult birds
that would normally stay farther north to migrate south.
•It is unknown whether or not disease played a role in low HY
numbers.